Learning objectives
Knowledge and understanding:
At the conclusion of the teaching program, the student will have acquired basic knowledge in the context of thermodynamics, fluid flow and heat transfer. With regard to the topics of thermodynamics and heat transfer he will also be able to outline some simple practical problems, highlighting the relevant physical phenomena.
Applying knowledge and understanding:
The student will be able to analyze simple energy and thermal problems, after schematization of the system and its interactions with the boundary.
Making judgments:
At the conclusion of the learning process, the student must possess the tools to critically interpret energy and heat transfer processes.
Communication skills:
The student must possess the ability to outline the problem, presenting clearly and with properties of language the details of the physical phenomenon and the results of the analysis.
Prerequisites
The student will have acquired the basic knowledge in the field of energy and heat transfer that will enable him to deal with courses or training which are mostly geared to applications.
Course unit content
The course includes the following main topics: thermodynamics, fluid flow, heat transfer. For each topic, the basic definitions are presented first, then the physical laws underlying the phenomena considered. With regard to the thermodynamics, the fundamental principles, with its corollaries, are presented and discussed in detail. The analysis is then extended to the description of fluid systems (gases and liquids) and gas mixtures (mixtures of air and water vapor). The study of the motion of fluids is limited to what is necessary for the study of heat convection; are also analyzed some problems relating to the motion of compressible fluids. In the third theme, the different heat transfer mechanism: conduction, convection, radiation, will be explored in more detail. Finally, the basic law of thermodynamics and heat transfer are applied to solving some heat transfer problems which are particularly significant for the mechanical engineer. During the course, some simple problems of thermodynamics and heat transfer are presented and discussed, with the aim to facilitate the assimilation of the theoretical concepts presented.
Full programme
Thermodynamics. Basics of systems of measurement units. Introduction and definitions. Closed systems. First law of thermodynamics and internal energy. Second law of thermodynamics and entropy. Irreversibility. Theorem of not decrease of entropy. Simple one-component systems. The (p, v, T) surface and (p, v) and (p, T) diagrams. Properties of liquids. Properties and transformations of saturated and superheated vapour. Ideal gas: definition and properties. Thermodynamic diagrams (T, s) and (h, s). Simple multi-component systems. Mixtures of ideal gases. Mixtures of air and water vapour. Thermodynamic properties of mixtures of air and water vapour: title, humidity, specific enthalpy. Psychrometric chart. Dew-point temperature and adiabatic saturation. The psychrometer. Thermodynamics of open systems. Definitions. Balance equations of mass and energy. Thermodynamic cycles: Rankine cycle and cooling cycle. Fluid Dynamics. Physical aspects of the motion of a fluid. Viscosity. Laminar and turbulent flow. Boundary layer. Material derivative. Continuity equation. Navier vectorial equation. Non dimensional form of the isothermal equations of motion. Reynolds number. Bernoulli's equation. Measures of fluid speed and mass flow rate. Compressible fluids. Mach number. Acoustic waves equation. Compressible fluid flow in ducts with variable section. De Laval nozzle. Heat transfer. Conduction. Fourier law. Thermal conductivity. Steady state heat conduction. Electrical analogy. Heat convection. Forced, natural and mixed convection. Energy balance equation. Non dimensional form of the non-isothermal equations of motion. Prandtl number, Grashof number, Nusselt number. Thermal radiation: introduction and definitions. Black body radiation laws: Stefan-Boltzmann’s law, Planck's law, Wien's law, Lambert's law. Kirchhoff’s law. View factor and its properties. Mutual thermal radiation between surfaces. Simultaneous presence of different modes of heat transfer. Global heat transfer coefficient. Tube in tube heat exchanger. Thin fin.
Bibliography
Testo consigliato:
M.J. Moran, H.N. Shapiro, B.R. Munson, D.P. DeWitt, “Elementi di Fisica tecnica per l’ingegneria”, McGraw-Hill
Ulteriore materiale bibliografico:
Y. A. Çengel, “Termodinamica e trasmissione del calore”, McGraw-Hill.
Appunti del corso, disponibili presso il Centro Didattico d’Ingegneria.
Teaching methods
Both the theoretical framework and the development of sample cases, will be carried out in the classroom on the blackboard.
Assessment methods and criteria
The exam is based on an oral test preceded by a written test, in which two simple problems, one of thermodynamics and one of heat transfer, which require the application of basic principles, are proposed. The resolution of the proposed problems without serious conceptual mistakes constitutes a constraint of admission to the oral exam, in which the correct and complete response to theoretical questions and the exposure property are evaluated. Nor texts, nor lesson notes can be used during the tests. The outcome of the written test is communicated immediately after the correction, usually within one or two days, via e-mailed communication to the students registered for examination. The final vote is communicated immediately at the end of the oral test, before its registration. The praise is added in case of excellent score in each item (written test and oral exam) and in case of particular communicative and speaking ability with reference to the specific field.
Other information
Further information is available at http://elly.dia.unipr.it
